Generally, a drain arrangement of an air conditioner is provided with a partition wall in order to separate an air introduction side of a heat exchanger from an air discharge side thereof, for example, referring to JP-U-64-28716. A predetermined gap is arranged between a bottom surface of the heat exchanger and a drain pan of the drain arrangement. In this case, a clogging due to dust and the like in the gap is restricted, and condensed water is guided to drop onto the drain pan.
However, in this case, a groove is formed at a lower surface of the partition wall or a bottom surface of the drain pan to guide condensed water to a drain discharge hose. Therefore, air to be conditioned will leak through the groove to bypass the heat exchanger.
Referring to a comparison example as shown in FIG. 10, the space between a bottom surface of a heat exchanger 131 and a drain pan 112 is completely partitioned by a partition wall 140. Two drain holes 113 are respectively disposed at an air upstream side and an air downstream side with respect to the partition wall 140. Condensed water flowing through the drain holes 113 is converged at a confluence portion 115a of a discharge pipe 115, and discharged through the discharge pipe 115, as indicated by the broken-line arrows in FIG. 10. As a result, the air upstream side is communicated with the air downstream side at the confluence portion 115a, as indicated by the solid-line arrows in FIG. 10. Therefore, in this case, air to be conditioned cannot be restricted from bypassing the heat exchanger 131.